Exercise devices have been developed for increasing strength, balance, or ability for a particular sport. Many of the devices incorporate a balance ball or half-ball of some sort, either with or without a board disposed on the ball, and with or without components that allow arm exercises. A classic balance board includes a round platform of 16-20 inches in diameter with a hemispherical fulcrum projecting from a bottom surface. The top surface may include non-slip material such as rubber.
Classic balance boards are limited in the types of exercises a user can do, and in the range of muscle groups that can be strengthened using the devices. Of course there are numerous modifications of the basic balance board, such as providing a fulcrum on the bottom of a skateboard-like platform and the like. Bintiva LLC of Lakewood, N.J. (among others) sells an adjustable balance board which comes with multiple fulcrums that can be replaced for different heights. U.S. Pat. No. 9,364,716 to Kramer also discloses an exercise board with interchangeable center and lateral accessories. Of course, these products create a problem of storing the unused fulcrums or accessories. Other balance boards featuring adjustable heights or robust springs are prohibitively expensive. Consequently, there remains a need for a simple yet more versatile transformable balance board.